Highly conductive fluoropolymer-based composite ink for printed stretchable electronics

Abstract

The recent development of stretchable electronics expands the scope of wearable and healthcare applications. This creates a high demand in stretchy conductor that can maintain conductivity at high strain conditions. Here, we describe a simple and novel fabrication way to achieve stretchable, 3Dprintable and lowcost conductive composite ink. It can be favorable in printing the complex stretchable patterns with high conductivity. Such elastic ink is composed of silver(Ag) flakes, fluorine rubber, an organic solvent and dispersive agent. The dispersive agent must be compatible with the chosen fluorine rubber as it accounts for multiple roles in the composite which promotes compatibility between silver flakes and fluorine rubber and also affects the mechanical properties of the hosting fluoropolymers as well as adhesion properties of the composite. Based on experimental observations in our work, we discuss the exact role of the dispersive agent in the composite. The resulting composite exhibits high conductivity value of 8.49 х104 S/m along with high reliability against repeated four stretching/releasing cycles. Interesting examples of transfer printing of the printed ink and its applications in working devices, such as conformal antennas and stretchable heater, are also showcased.